Medycyna Sądowa Wczoraj, Dziś i Jutro

Presentation

Good morning, ladies and gentelmen. I have been invited here to tell you about a very interesting issue, that concerns the forensic pathologists all over the world and may be the beginning of the new age in forensic medicine and other forensic sciences. My topic today is Virtopsy. The title of article I based is 'Postmortem multislice computed tomography and magnetic resonance imaging of odontoid fractures, atlantoaxial distractions and ascending medullary edema'.
I have divided my talk into five sections. Firstly, I would like to tell you what is the Virtopsy and what is the idea behind this term. My second point concerns its benefits. Everything has some disadventages, so in the third part I deal with them. After that I will tell you about non-invasive diagnostic possibilities in the post mortem examination of the injured craniocervical region connected with odontoid fractures, atlantoaxial distractions and ascending medullary edema. In the fifth part I will show you some other case-relevent findings of classical autopsy and Virtopsy.

1.    What is the Virtopsy?

The term "autopsy" ("autos" means "self", "opsomei" means "seeing with eyes"), was
adopted by medical sciences and is used as a synonym for the dissection of human bodies. As implicated by the word itself, in fact even today, the autopsy procedure is a subjective method, and in the conventional forensic investigation process the description of the autopsy results is based on descriptive linguistic techniques.
The main aim of the virtopsy project is to eliminate the subjectivity. The term "virtopsy" was born in Switzerland, including the two terms "virtual" and "autopsy" but deleting "autos". Virtopsy was born from the desire to implement new techniques in radiology for the benefit of forensic science. There have been great improvements in MSCT and MRI technology, increasing both contrast and resolution and offering possibilities of 2D and 3D reconstruction. The aim of Virtopsy is to establish an observer independent, objective and reproducible forensic method using modern imaging technology, leading to minimally invasive "virtual" forensic autopsy analogous to "keyhole surgery" in clinical medicine.
What about the technical equipment? The full and optimal set of diagnostic tools is called 'Virtobot'. What does the 'Virtobot' consist of?
"    Heartlungmachine, used for post mortem angiography with an artificial
circulation.
"    Multislice CT-scanner with flouroscopy , MRI machine and an two external, network connected workstations (one in the autopsy room and another one in the VIRTOPSY-facilities).
"    3D Surface scanner - an optical measuring machine, based on the principle of triangulation.
"    CT- image guided biopsy-system - the radiological imaging has to be supplemented by careful tissue sampling to facilitate further examination.
"    the anonymity of the deceased is preserved by wrapping the corpses in artifact-free body bags.

2.    Advantages
What are the benefits of Virtopsy?

    o Uniform Documentation of Findings The present-day descriptive, subjective protocoling of autopsy findings can be replaced by an uniform and observer-independent, objective radiological documentation. This will increase the quality of the evidence presented in court by experts. The radiological data can be used for 2D and 3D reconstructions which can be stored indefinitely,  viewed in all planes and turned in every direction. The digitally stored images, can easily be sent for outside review or even posted on a Web site. Quality control become possible, as well as forensic "telemedicine" consultation.
    o Increased Understandability The availability of 2D and 3D Reconstructions will impressively improve the clarity and, consequently, the understandability of future experts' evidence. This will play an important role in the acceptance of the evidence.
    o Virtopsy reduces the stress of the deceased person's family membrs and friends
    o Alternative for cultures where conventional autopsy is forbidden Virtual autopsy will allow for medico legal examinations in cultural circles where a conventional autopsy is stigmatized or even forbidden.
    o  Last but not least benefit, the method could be useful in the examination of highly infectious bodies.

3.    Disadvantages

Now, we can turn to disadvantages of this new procedure. The most important disadventage is, of course, high cost of diagnostic tools especially MRI machine which costs even 1 000 000 $. Secondly, you can't estabilish the colour of organs and detect discharge from the vascular system. Also due to metal artefacts resulting from, for example, the surgical screw fixation, MR imaging cannot be used. Another problem is more complicated, specific software for MRI and MSCT.

4.    Examination of the injured craniocervical region - odontoid fractures, atlantoaxial distractions and ascending medullary edema

Let me turn now to the issue of traumatic injuries of the craniocervical region. They are probably underdiagnosed. Even if an autopsy is performed, lesions of the dorsal neck region might be overlooked. Dorsal neck dissection techniques are vastly invasive, and when the upper spine is extracted the corpse is less well preserved than after a routine autopsy. In certain cases bone maceration techniques have to be applied which require hours to days, so it extending the examination. Autopsy procedure is often suplemented by plain radiographs which aid in the search for skeletal lesions, however, using of conventional X-ray examination it is difficult to detect fractures of the dens axis because in majority open-mouth rentgenograms cannot be carried out due to postmortem rigor of the jaw musculature.
Due to all these reasons professor Thali from Switzerland carried out the study to determine the value of postmortem neck imaging. For this purpose 5 deceased persons who had suffered odontoid fractures or atlantoaxial distractions with or without medullary injuries, were studied using MSCT and MRI and subsequent classical autopsy. Evaluation of the findings was performed by radiologists, forensic pathologists and neuropathologists. The cause of death could be established radiologically in three of the five cases.
Fractures of the odontoid process comprise 10-15 % of all fractures of the cervical spine and are often caused by motor vehicle accidents or falls from weight. The incidence of craniocervical distractions is lower. Traumatic brain stem lesions are frequently associated with craniocervical injuries and have great importance in forensic reconstruction. Edema ascending to the respiratory and circulatory centers located in the brain stem might lead to death of the patient. Ascending medullary edema could explain the sometimes surprising onset of death in patients who have suffered odontoid fractures and were treated for several days without major complications.
I do not have enough time to describe you all studied cases, so I choose one of them. A 20-year-old male was hit by a car from behind while riding his bicycle. Immediate death was due to transection of medulla. What did the imaging methods show? A dislocation of the craniocervical joint was clearly visible in the MSCT scans. The odontoid process showed posterior displacement. No fractures of the cervical vertebrae were apparent. MRI depicted the dislocation with the accompanying ligament injuries. Subarachnoid hemorrhage was found. What about autopsy? It revealed dislocation of the joint between the first and second cervical vertebrae and complete transection of the spinal cord. Intracranially, a thin subdural blood layer was present. In this case the cause of death could be determined before autopsy by radiological imaging.

5.    Autopsy versus Virtopsy

Okay, now I want to show you some pictures.
1.    The first picture shows the current method of showing a bullet exit wound and skull fracture - maceration (right) compared to a 3D reconstruction with computer simulations of impact (left and down).
2.    Next picture is connected with the air in the heart. Massive filling of the heart cavities with air causes the death in many traumatic cases. In that cases at autopsy small bubbles escape from the right chamber when it is punctuated. The MR-image shows the air within the heart invasive method.
3.    The third picture shows knife wound to the heart: autopsy and MR finding.
4.    The fourth picture - death by hanging. 3D reconstruction of the CT data shows the fracture of the horn of the hynoid bone. The same finding is even more difficult to find at autopsy because of the surrounding tissue.
5.    Another picture - a case of a bicycle/motor vehicle accident with one impact point at the right backside. The MR-image shows clearly demarcated soaking with blood of the damaged tissue. The same case at autopsy - the hematoma is not that well distinguished.
6.    The last picture shows the procedure of Virtopsy imaging. Visualisation of a gunshot wound through the cerebellum by showing the bony details using CT. Clearly visible is the typically tunnel shaped exit wound. After that comparative visualisation of the soft tissue damage along the bullet track within the cerebellum using MRI. This picture shows detailed visualisation of the bullet track. Searching the bullet track at autopsy in the traditional way using a probe is even more difficult.

Summing up then, as shown in the study, both MI and MSCT offer new, non-invasive diagnostic possibilities in the postmortem examination, especially of the injured craniocervical region. Because motion artefacts are absent and examination times are basically unrestricted, the quality of the imaging is often superior to the results achieved in clinical practice. The possibility of 2D and 3D image data processing significantly facilitated forensic reconstruction of the course of events. Are Bloodless, Noninvasive Autopsies the Future of Forensic Medicine? - We will see :

Thank you very much.